# 变量
message = "hello world!"
print(message)

# 定义变量
a = 10
# 使用变量
print(a)

#修改变量的值
a = 20
print(a)

a = 10
b = 20
a = b
print(a)
print(b)

print()
print()
print()
print()
x = 10
print(type(a))

x1 = -10
print(type(a))


print(2 + 3)
print(2 - 3)
print(2 * 3)
print(2 / 3)

print(2 + 3 * 4)
print((2 + 3) * 4)


a = 12.25
print(type(a))

a = -12.25
print(type(a))


print(4 / 2)
print()

print(1 + 2.0)
print(2 * 3.0)
print(3.0 ** 2)


print(1 > 0)
print(1 < 0)


s = "hello python"
print(s)
